Multicolored unitary self-supported polymer matrix transfer medium

ABSTRACT

A MULTICOLOR TRANSFER MEDIUM IS PROVIDED BY A PROCESS WHICH COMPRISES MAKING A FIRST MATRIX MATERIAL BY MIXING A FLUID TRANSFER INK OF A FIRST COLOR WITH A SOLUTION OF A FILM FORMING POLYMER IN A SOLVENT FOR THE POLYMER, COATING THE RESULTING DISPERSION ON A FIRST SUBSTRATE AND EVAPORATING THE SOLVENT TO FORM THE MATRIX MATERIAL OF A FIRST COLOR. A MATRIX MATERIAL OF A SECOND COLOR IS FORMED IN AN IDENTICAL MANNER UTILIZING A FLUID TRANSFER INK OF A SECOND COLOR. THE TWO SUBSTRATES SUPPORTING THE MATRIX MATERIALS ARE   THEN PLACED IN ADJACENT EDGE ALIGNED RELATIONSHIP TO ONE ANOTHER ON A THIRD SUBSTRATE WHICH HAS BEEN COATED WITH A FUGITIVE ADHESIVE AND A POLYMER IS THEREAFTER BACK COATED OVER THE TWO MATRIX MATERIALS TO SEAL THEM TOGETHER. THE RESULTING UNITARY MULTICOLORED TRANSFER MEDIUM IS THEN STRIPPED FROM THE SUBSTRATES AND SLIT, IF REQUIRED, TO A DESIRED WIDTH.

Aug. 1, 1972 H. T. FINDLAY ETAL 3,

MULTICOLORED UNITARY SELF'SUPPORTED POLYMER MATRIX TRANSFER MEDIUM FiledDec. 14, 1970 gig-12 1:: O0 08 a, 0

INVENTORS HUGH T. FINDLAY JERRY F. STONE By M w SUBSTRATE A] Town;

' US. or. 161-166 ABSTRACT OF THE DISCLOSURE A multicolor transfermedium is provided by a process which comprises making a first matrixmaterial by mixing a fluid transfer ink of a first color with a solutionof a film forming polymer in a solvent for the polymer, coating theresulting dispersion on a first substrate and evaporating the solvent toform the matrix material of a first color. A matrix material of a secondcolor is formed in an identical manner utilizing a fluid transfer ink ofa second color. The two substrates supporting the matrix materials arethen placed in adjacent edge aligned relationship to one another on athird substrate which has been coated with a fugitive adhesive and apolymer is thereafter back coated over the two matrix materials to sealthem together. The resulting unitary multicolored transfer medium isthen stripped from the substrates and slit, if required, to a desiredwidth.

BRIEF BACKGROUND OF INVENTION 1 Field This invention relates broadly toa novel transfer medium useful as carbon paper, typewriter ribbon or thelike. More specifically the present invention is directed to reusablemulticolored plastic transfer elements and to methods for making suchtransfer elements.

(2) Description of the prior art Multicolored transfer elements now incommon usage may be generally classified in the following two broadcategories: Ink impregnated woven fabrics and single use carbon paperand carbon film materials. The multicolored woven fabric is generallyproduced by passing the fabric over a split inking roller having thevarious colored inks located thereon in a manner to transfer the inkfrom the roller to the' fabric. Great care must be taken to insureproper alignment of the fabric with the roller to insure ribbonuniformity. Further, great care must be taken in the selection of theinks utilized to insure that they have proper thixotropy and bleedcharacteristics. Also, due to the caliper of the fabric, the impregnatedwoven fabric ribbons are characterized by lack of conformity of thefabric to the type face under impact and this results in a low qualitytransfer. This low quality transfer is further aggravated by the lack ofdyestuif that is characteristic of fabric two color ribbon inks (thelack of dyestuif insuring ink separation).

Conventional single use carbon paper and film ribbons have relativelyhigh quality transfer characteristcs, but, due to their extremely thincaliper and structure, must be disposed of after single use. Variousmethods have been devised for making multicolored film ribbons such asto thermally couple or adhesively couple such ribbons to a substratewhich remains as an integral part of the ribbon. While such a ribbon isof thicker caliper than a single United States Patent color ribbon, itis still not reusable because of the total transfer characteristic ofsuch ribbons. Accordingly, when such a medium is utilized for atypewriter ribbon, the ribbon is passed through the machine one time'with the result that only one portion of the medium (that portioncontaining the selected color) is utilized.

A third type of transfer medium has been suggested in the prior art:reusable porous polymer films. An example of such a medium is fullydescribed in US. Pat. 3,413,- 184 entitled Transfer Medium and Methodfor Making Same. Such a medium comprises a solid, continuous porousmatrix containing globules of a liquid or jelled ink within the pores. Awide variety of inks may be utilized in conjunction with such a medium,the only constraint on the ink being that it is relatively insoluble inlow concentration of the solvent in which the polymer and ink aredispersed during the manufacturing process. When a transfer medium isconstructed in accordance with the afore referenced Pat. 3,413,184, theresulting material is of a thin caliper, but yet the spongy likeconstruction of the thin caliper material allows it to be used over andover. Since the ink and resin are dispersed in a liquid-form during themanufacturing process, casting of more than one color ink and matrixsimultaneously results in intermixing and contamination of one coloredmatrix with another. Further, it is not possible to manufacture amulticolor polymer film utilizing conventional multicolor fabric ribboninking or those multicolor carbon film material techniques which requirethermal bonding. Although a multicolor medium could be produced bycoupling two matrix materials to a substrate layer in aligned relationutilizing the adhesive approach heretofore taught in the formation ofcarbon films of multiple colors, the resultant product would be ofthicker caliper and great care would have to be taken in selecting aproper substrate medium and adhesive which would co-act with the thuscoupled transfer medium in a manner to produce legible and consistantgraphic symbols when utilized in an environment such as a typewriter.That is, the selection of the adhesive and substrate vary the transfercharacteristics of the medium and unless great care is utilized inselecting these components, a ribbon having the attributes of thepolymer matrix would not result.

SUMMARY In order to overcome the above problems and shortcomings of theprior art and to provide a multicolored unitary spongeous transfermedium, the transfer medium of the present invention is formed duringthree separate operations. During the first operation, a matrix materialof a first color having varying porosity throughout horizontal zonesthereof is formed on a first temporary substrate in a manner similar tothat described in US. Pat. 3,413,184. Thereafter, a second matrixmaterial of a second color is formed on a second substrate in ananalogous manner. The two substrates supporting the matrix materials arethen placed in edge aligned relation on a sup port substrate containinga liquid adhesive. The liquid adhesive facilitates initial lateralmovement of the material carrying substrates in order to effect theprecise alignment of the substrates and also couples them to the supportsubstrate. Thereafter, a back coating of the polymer is applied over thetwo matrix materials and the exposed portions of the substrates. Theback coating is continuous with the polymer phase of the matrixmaterials and forms a barrier between the discrete colored strips. Thediscrete separation between the colored strips and the barrier preventbleeding of inks of one color strip to the other. The liquid adhesiveprevents excessive penetration of the polymer to the substrate. Thetransfer medium is then stripped from the substrates and the medium maybe slit to desired widths.

The invention will be better understood in the light of the followingdescription and claims and the accompanying drawings which illustrate,by way of example, a preferred mode for carrying out the presentinvention.

In the drawings:

FIG. 1 is a schematic side elevational view of a system or apparatus forcarrying out the process of the present invention.

FIGS. 2a, 2b, 2c, 2d, and 2e are edge views of the transfer medium as itis manufactured.

As described in the aforereferenced Pat. 3,413,184, the continuousporous matrix of the transfer medium can be made of a suitable syntheticpolymer which includes the following: polyamide resins such as nylon,polyurethane, polycarbonates, polyethylene, polypropylene, polyvinylacetate, polyvinyl chloride, vinyl chloride, acrylonitrile butadiene,cellulose acetate butyrate and cellulose acetate. Other synthetic resinsor mixtures of synthetic and natural resins capable of forming thin,self supporting porous matrices may be substituted for the foregoingwithout departing from the scope of the invention. The exact compositionof the inks incorporated in the pores of the polymer matrix is notcritical and may be in the form of either a fluid ink or a jellied ink.One requirement of the ink is that it not be soluble in the polymermatrix. An additional requirement is that it is non volatile attemperatures used to form the matrix. Thus, most oil base dye solubleinks, Water base dye soluble inks and pigmented thixotropic inks withand without dyes, could be used. In accordance with the disclosure ofthe aforementioned patent, the polymer is dissolved in a volatilesolvent and the ink is distributed in the polymer solution. Thissolution is then coated on a temporary heat stable substrate such as apaper web or an endless belt of Mylar. The solvent is then evaporated,and during this action, a relatively high concentration of plastic isobtained at the upper surface and a higher concentration of ink isobtained at the lower surface adjacent to the temporary substrate.

According to the present invention, a plurality of polymer matrixtransfer materials each of dilfering colors are formed as describedabove on a like plurality of temporary substrates. The substratesupported matrix materials are then slit to required widths withoutpeeling them from their substrates. A temporary heat stable supportsubstrate is then prepared by coating it with a film of liquid adhesive.The adhesive may be a fugitive adhesive such as a solution of water andwetting agent (e.g. polyethylene glycol) or isopropanol and glycerin ora permanent adhesive such as ethylene acetate copolymer or acrylonitrilebutadiene or a hot melt adhesive (e.g. wax blends). A plurality of slitmatrix material supporting substrates are then placed in edge alignedrelationship on the adhesive layer of the support substrate. The film ofadhesive facilitates initial alignment of the matrix material supportingsubstrates with respect to one another permitting lateral movement ofthese substrates over the support substrate. When a fugitive adhesive isused it is partially evaporated and absorbed causing the matrixsupporting substrates to become temporarily but firmly adhered to thesupport substrate. Conventional adhesives and hot melt adhesivessolidify to permanently join the substrates. With the substrates thuscoupled, movement of the substrates with respect to one another isprevented during subsequent handling and coating operations.

A back coating of a polymer material preferably of the same polymermaterial utilized to form the matrix materials is dissolved in a solventand applied over the matrix materials and the exposed portions of thesubstrates. The applied polymer penetrates between the matrix materialsto form. a minute barrier layer between the substrate supported matrixmaterials. The adhesive located on the support substrate preventsexcessive penetration of the support substrate by the polymer material.The solvent is evaporated leaving an integral solvent bonded polymerfilm on the top surface of and bet-ween the matrix materials. The matrixmaterials and the polymer film bonded thereto are then peeled from thetemporary substrates resulting in a unitary multicolor transfer medium.The edges of the transfer medium can thereafter be slit to obtain amedium of a desired Width and to remove excess polymer material.

It has further been found that when a polymer receptive supportsubstrate is utilized, and when the matrix material supportingsubstrates have clear edge definition, the back coated matrix materialsmay be stripped from the substrates leaving the excess back coatedpolymer material with the substrates resulting in a unitary transfermedium having clearly defined straight edges which require no furtherslitting operation.

The present invention will be better understood in light of thefollowing detailed examples:

EXAMPLE I A three color transfer element in accordance with the presentinvention is prepared in the following manner:

(1) A black color ink and filler dispersed in a nylonethyl alcoholsolution is prepared by following steps (1) through (4) of Example I ofthe afore referenced US. Pat. 3,418,184. This mixture is coated onto atemporary 1 mil thick Mylar substrate and dried in the exact mannerdescribed in the afore referenced patent resulting in a one mil thickblack matrix material film layer on the Mylar substrate. The inkdistribution within the matrix is non uniform as described in thepatent. The substrate and film are then wound onto a take up reel.

(2) A red color ink and filler dispersed in a nylonsolvent solution isprepared in the following manner:

(a) A solvent mixture of 5 parts isopropyl alcohol, (isopropanol) 4 /2parts ethyl alcohol (ethanol) and /2 part water is prepared by stirringat room temperature.

(b) One part by weight of nylon is dissolved in a suflicient quantity ofsol-vent mixture prepared in step (2a) to produce a solution containing12% nylon and 88% solvent. The solution is obtained by mixing the nylonand solvent mixture in a Cowles dissolver at a temperature of 140 F.Stirring expedites the solution.

(0) The following ink ingredients are weighed into a steel ball mill andare milled for approximately 8 hours:

Ingredient: Percent by weight Modified polyvinyl pyrrolidone polymer(Ganex V 216 produced by General Aniline and Film Corp.) 35

Low viscosity oil (Kronisol R-9 produced by Ohio Apex Corp.) 30

Red pigment (Irgazin Red 2BLT produced by Geigy Chemical Corp.) 35

Total (d) Three parts by weight of diatomaceous earth is mixed with thenylon-solvent solution prepared in step 2b until the admixture ishomogeneous.

(e) Five parts by weight of the ink prepared in step 20 is then slowlyadded to the mixture of filler and the nylonsolvent solution prepared instep 2d under high speed agitation in a Cowles dissolver, until completedistribution of the ink and filler in the nylon solution is obtained.

The mixture obtained in step 22 is coated onto a temporary 1 mil thickMylar substrate and dried in the exact manner described in theafore-referenced patent resulting in a one mil thick red matrix materialfilm layer on the Mylar substrate. The substrate and film are wound ontoa take up reel.

(3) A blue-black color ink and filler dispersed in a nylon-solventsolution is prepared as in step 2 except the following ink ingredientsare utilized in place of those specified in step 20.

The mixture is coated as in steps 1 and 2 resulting in a one mil thickblue-black matrix material film layer on a 1 mil Mylar substrate. Thesubstrate and film are wound onto a take up reel.

(4) All substrate supported matrix material prepared in roll form insteps 1-3 is slit to required ribbon width and rewound in roll form. Thematerial prepared by step 1 is slit to a width of 0.4 and the materialsprepared by steps 2 and 3 are slit to a width of 0.021".

(S) A solution of 95% by weight water and 5% by weight polyethyelneglycol 400 monolaurate (Aldosperse L9 produced by Glyco Chemicals Inc.)is prepared by stirring at room temperature.

(6) Three parts by weight of nylon is dissolved separately in athree-to-one mixture of ethyl alcohol and water by stirring in a Cowlesdissolver at 140 F. to produce a solution of 5% nylon and 95% ethylalcohol and water.

Referring now to FIG. 1 of the drawings, all cut matrix material in rollform (Step 4) is mounted on shafts 11 and 13. The matrix materials 15,17 are staggered with respect to each other on the two shafts and placedin the required order of the finished transfer element, the widermaterial being located intermediate the narrow material. A 2 mil Mylarsubstrate 19 is mounted on supply shaft 21. The water-polyethyleneglycol solution (Step 5) is placed in tank 23 and wiped onto the 2 milMylar substrate to form a 0.1 mil film on the substrate. The substrateis then passed over the guide roller 24 with the film side up. Thematrix materials are taken from their respective supply rolls and areedge aligned as they pass through the spring mounted concave guidepulley 25. The Mylar substrate side of the matrix materials is thenlocated over the 2 mil Mylar substrate at the guide roller 24. Thewater-polyethylene glycol film initially facilitates lateral movement ofthe matrix supporting Mylar substrates to effect perfect alignment. Thematerials are then passed through a Gardner applicator 27 containing thenylonethyl alcohol mixture (step 6) which deposits 0.5 to 1.0 mil drynylon on the back surface of the matrix materials. The back-coatedmatrix materials are then passed through a drying oven where an averagetemperature of 180 F. is maintained to disperse the solvent from thebackcoated nylon and form an integral solvent bonded nylon film on thetop surface of the nylon matrix materials. The unitary back coatedmatrix materials are then stripped from the one mil thick supportsubstrates and the two mil support substrate which is attached to theone mil substrates and are wound on reel 31. The one mil substrates areseparated from the two mil substrate (the fugitive adhesive bond isbroken) and wound on reel 33. The two mil substrate is wound on reel 35.The transfer element on reel '31 may thereafter be slit to appropriatewidth, it being understood that a multiplicity of three colored transferelements are formed in side by side relationship on a single 2 mil thickMylar substrate. The finally slit transfer elements may then be woundonto small spools to obtain a three color typewriter ribbon.

6 EXAMPLE 11 A three color transfer element in accordance with thepresent invention is prepared in the following manner:

(1) Black, red, and blue matrix materials are prepared on one mil thickMylar substrates in accordance with the methods described in steps 1-4of Example I.

(2) A solution of 98% by weight isopropyl alcohol and 2% by weightglycerol is prepared by stirring at room temperature.

(3) A nylon back coating is prepared according to step 6 of Example I.

(4) The solution of step 2 is placed in the tank 23 of FIG. 1 and a 1.2mil thick roll of highly calendered, low porosity glassine papersubstrate material is mounted on the supply shaft 21. The glassine paperis wetted by the isopropyl alcohol-glycerol solution which conditionsthe substrate to make it receptive to nylon.

(5) The substrates of the matrix materials are applied over the filmside of the glassine paper, the nylon backcoating is then applied andthe backcoated transfer element is dried as described in Example I.

(6) The transfer element is then stripped from the substrates and wound,it being unnecessary to thereafter slit the transfer element.

FIG. 2 illustrates an enlarged, schematic edge view of the transferelement prepared according to Example II. FIG. 2a illustrates the redmatrix material 51 located on its support substrate 53 the black matrixmaterial 55 located on its support substrate 57 and the blue matrixmaterial 59 located on its support substrate 61 after each substrate hasbeen prepared according to step 1. FIG. 2b illustrates the glassinepaper substrate 63 after its upper surface has been coated with theisopropyl alcohol-glycerol film 65. FIG. 20 illustrates the matrixmaterials 51, 55 and 59 and their associated substrates 53, 57 and 61 asthey rest on the film coated glassine paper substrate 63. FIG. 2dillustrates the materials of FIG. 20 after a nylon backcoating 67 hasbeen applied and dried. FIG. 2e illustrates the transfer element and thesubstrates after they have been stripped. The excess nylon backcoating69 remains with the substrate 63 which is more receptive to the nylonthan the edges of the nylon substrates 53 and 61, the attractive forceof the nylon to the substrate causing the nylon to break apart from thenylon coated transfer element along an edge thereof.

EXAMPLE III A transfer element was prepared in accordance with themethod described in Example II utilizing a 2 mil thick carbonizingtissue substrate wetted with a 0.1 mil thick film of theisopropanol-glycerin solution prepared according to step 2 of Example11.

EXAMPLE IV A transfer element was prepared in accordance with the methoddescribed in Example I utilizing the following water soluble inkformulation in lieu of the oil based formulation specified in the samepercent by weight amount:

Ingredient: Percent by weight Polyethylene glycol (Carbowax 200 producedby Union Carbide Corp.) Water soluble Nigrosine (Nigrosine W.S.B. 40

produced by American Cyanamid Corp.) 20

IAS already noted above, various materials including those described inExamples III, IV, and V of 1.1.8. Pat. 3,413,184 may be substituted forthe polymer, filler and inks described in the above examples withoutdeparting from the spirit of the present invention.

While there have been shown and described and pointed out thefundamental novel features of the invention as applied to the preferredembodiment, it will be understood that various omissions andsubstitutions and changes in the form and details of the deviceillustrated and in its operation may be made by those skilled in the artwithout departing from the spirit of the invention. It is the intention,therefore, to be limited only as indicated by the scope of the followingclaims.

What is claimed is:

1. A process for making a multicolor unitary spongeous transfer mediumcomprising:

coating on a first temporary substrate a mixture comprising a volatiledispersant, a resin and ink, said ink being incompatible with the resinand having a first color;

coating on a second temporary substrate a mixture comprising a volatiledispersant, a resin, and ink, said ink being incompatible with the resinand having a second color;

expelling said dispersants from said mixtures;

coating a third substrate with an adhesive layer;

aligning the first and second substrates on the adhesive layer in edgealigned parallel relation to one another; coating a resin and resinsolvent solution over the resinin-k mixtures and exposed substrates;

expelling said resin solvent;

stripping the transfer medium from the substrates.

2. The process for making a multicolor unitary spongeous transfer mediumset forth in claim 1 further comprising the step of slitting thetransfer medium into the form of a ribbon having the dimension desiredfor use as a typewriter ribbon.

3. The process for making a multicolor unitary spongeous transfer mediumset forth in claim 1 wherein said third substrate is coated with afugitive adhesive layer comprising a thin film of volatile fluid.

4. The process for making a multicolor unitary spongeous transfer mediumset forth in claim 3 wherein said fugitive adhesive conditions thesurface of the third substrate to be receptive to and bond with theresin coating.

5. A multicolor transfer element comprising a polymer film having aplurality of pores, a horizontal zone near one surface of the filmhaving significant relatively high density of said pores, a secondhorizontal zone near the opposite surface having a significantrelatively low density of said pores, globules of fluid transfer ink ofa first color in the pores located within a first vertical zone andglobules of fluid transfer ink of a second color in the pores in asecond vertical zone laterally adjacent to said first vertical zone.

6. The multicolor transfer element set forth in claim 5 furthercomprising a thin zone of polymer film of relatively low density ofpores located intermediate said first and said second vertical zones.

References Cited UNITED STATES PATENTS 3,101,668 8/1963 Leeds 101401.l

WILLIAM A. POWELL, Primary Examiner US. Cl. X.R.

